Preheat oven to 325 Deg F. Prepare a 9 inch springform pan. Line the bottom with a parchment circle and lightly oil the parchment.
In a medium bowl whisk together the flour, polenta, baking powder and salt. Set aside
In a bowl of a stand mixer or large mixing bowl combine the sugar and lemon zest and rub between your fingers until the zest is mixed in well and the sugar is fragrant. Add in the eggs and mix on medium high until thickened and light yellow in color.
Scrape down the sides of the bowl and add in the lemon juice, mascarpone, oil and vanilla extract and mix again until well combined. Add in the flour mixture and mix on low until no streaks of flour remain, do not over mix. pour batter into prepared pan and bake 30-35 min until golden yellow in color and the center bounces back when lightly pressed or a toothpick inserted into the middle comes out with just a few crumbs
Let cool for 5 minutes in pan, gently run a knife around edges to release cake, release springform and transfer cake to a wire cooling rack to cool at least 20 minutes before serving. Can be served warm or at room temperature.
While the cake is baking prepare the topping.
In a cold, stainless steel bowl whip the mascarpone cheese until light, about one minute. Add in the cold whipping cream and whip until semi-stiff peaks have formed. Add in the honey and vanilla extract and whip again. Taste and add more honey if desired.
Pipe swirls or rosettes around the edges of the cake and decorate with candied lemon circles. Serve.